This invention relates to a fuel dispensing system and method and, more particularly, to such a system and method in which two grades of fuel are adapted to be dispensed both individually and in a blended form.
Many gasoline service stations require the installation of multi-product fuel dispensers or pumps, each for dispensing a plurality of fuel products having different octane ratings at each fueling station. Several known systems of this type typically include a flow path for each fuel product from its storage tank to the outlet nozzle which dispenses it into the consumer's vehicle, and a valve disposed in the flow path for selecting the fuel to be dispensed.
There are problems associated with these types of delivery systems. For example, when the customer chooses a particular grade of fuel, the flow of the latter fuel through the system can cause an undesirable amount of mixing with the non-selected grade, especially if the latter was the last product to be dispensed. A major cause of this is that the end product being dispensed through its conduit will tend to either siphon or force the other product from its conduit and through the valve, depending on the particular arrangement of the dispenser. This, of course, results in an undesirable mixing of the products, resulting in a product being dispensed which does not have an octane rating that is selected by the customer.
Therefore, what is needed is a system and method for dispensing two or more discrete fuel products according to which the discrete fuels can be dispensed individually without the danger of being mixed with, and therefore contaminated by, the other fuel. This has the major advantage of assuring that the octane rating of the dispensed product corresponds to that selected by the customer.